Transmission terminal, transmission method, and computer-readable recording medium storing transmission program

ABSTRACT

A transmission terminal transmits video data and display data of a screen shared with another transmission terminal to the other transmission terminal via a predetermined relay apparatus. The transmission terminal includes a storage unit that stores relay apparatus information of the relay apparatus to which the transmission terminal transmits the video data; a receive unit that receives the display data from an external input apparatus connected to the transmission terminal; and a transmitting unit that transmits the display data received by the receive unit to the relay apparatus indicated by the relay apparatus information stored in the storage unit.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application of and claims thebenefit of priority under 35 U.S.C. §120 from U.S. application Ser. No.14/632,301, filed Feb. 26, 2015, which is a continuation of U.S.application Ser. No. 13/643,827, filed Oct. 26, 2012, now U.S. Pat. No.9,001,179, which is a national stage of International Application No.PCT/JP2011/060676, filed Apr. 27, 2011, which is based on and claims thebenefit of priority under 35 U.S.C. §119 from Japanese PriorityApplications No. 2010-106610 filed May 6, 2010, No. 2010-195692 filedSep. 1, 2010, and No. 2011-064073 filed Mar. 23, 2011, the entirecontents of each of which is hereby incorporated by reference.

TECHNICAL FIELD

The disclosure generally relates to a transmission terminal capable oftransmitting and receiving display data of a screen shared with anothertransmission terminal.

BACKGROUND ART

Time and monetary expenses for business trips and the like may bereduced by conducting a video conference. The video conference may beeffected by transmitting and receiving video data and audio data betweenplural transmission terminals by using a transmission system based on acommunication network, such as the Internet. Due to improvements inbroadband technology in recent years, it is now possible to transmit orreceive high-quality image and audio data. As a result, participants ofa video conference can not only monitor the situation on the other endof the communication line but also communicate verbally with one anotherwith an improved level of understanding.

During the video conference, the conference participants may discussmaterial displayed on the screen of a computer separate from thetransmission terminal on one end of the transmission line. In such acase, a participant on the one end may wish to transmit the data of thedisplayed material (which may be referred to as “display data”) toanother participant across the communication network so that they canshare the same material, in addition to transmitting audio data or videodata from one party to the other.

U.S. Pat. No. 6,760,749 B1 discusses a technology whereby the displaydata of a material, which is referred to as “presentation content” inthe related art, is transmitted together with the audio and video datato a distributing apparatus during a telephone conference via a network.The distributing apparatus then distributes the data or otherinformation to transmission terminals. In this way, the video conferenceparticipants can refer to the same material while listening to orlooking at each other during the video conference.

However, in the above related art, when the material (presentationcontent) is managed in a computer other than the transmission terminalfrom which the video or audio data is transmitted during the conference,the computer needs to be placed under the management of a transmissionmanaging system. As a result, the processing load of the transmissionmanaging system increases.

SUMMARY OF INVENTION

Accordingly, it is a general object of the present invention to overcomethe problem of the related art. A more specific object may be to providea transmission terminal capable of allowing display data stored in anexternal input apparatus to be transmitted without logging the externalapparatus into a transmission managing system, thus preventing theincrease in the processing load of the transmission managing system.

In one aspect, a transmission terminal for transmitting video data anddisplay data of a screen shared with another transmission terminal tothe other transmission terminal via a predetermined relay apparatusincludes a storage unit configured to store relay apparatus informationof the relay apparatus to which the transmission terminal transmits thevideo data; a receive unit configured to receive the display data froman external input apparatus connected to the transmission terminal; anda transmitting unit configured to transmit the display data received bythe receive unit to the relay apparatus indicated by the relay apparatusinformation stored in the storage unit.

In another aspect, a transmission method performed in a transmissionterminal that transmits video data and display data of a screen sharedwith another transmission terminal to the other transmission terminalvia a predetermined relay apparatus includes storing relay apparatusinformation of the relay apparatus in a storage unit of the transmissionterminal; receiving the display data from an external input apparatusconnected to the transmission terminal; and transmitting the receiveddisplay data to the relay apparatus indicated by the relay apparatusinformation stored in the storage unit of the transmission terminal.

In another aspect, a computer-readable, non-transitory recording mediumstores a transmission program that causes a transmission terminal toperform the transmission method.

These and other objects, features and advantages of the invention willbe apparent to those skilled in the art from the following detaileddescription of the invention, when read in conjunction with theaccompanying drawings and appended claims.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates a transmission system according to an embodiment ofthe present invention;

FIG. 2 is a perspective view of a transmission terminal according to thepresent embodiment;

FIG. 3 is a block diagram of a hardware structure of the transmissionterminal;

FIG. 4 is a block diagram of a hardware structure of a transmissionmanaging system, a relay apparatus, a program providing server, or anexternal input apparatus according to the present embodiment;

FIG. 5 is a functional block diagram of the transmission terminal, therelaying apparatus, the external input apparatus, and the transmissionmanaging system of the transmission system according to the presentembodiment;

FIGS. 6A, 6B, and 6C illustrate images of various image qualities;

FIG. 7 is a modified quality managing table;

FIG. 8 is a relay apparatus managing table;

FIG. 9 is a terminal authentication managing table;

FIG. 10 is a terminal managing table;

FIG. 11 is a destination list managing table;

FIG. 12 is a session managing table;

FIG. 13 is an address priority managing table;

FIG. 14 is a transmission rate priority managing table;

FIG. 15 is a quality managing table;

FIG. 16 is a sequence chart of a process of managing operating statusinformation of relay apparatuses;

FIG. 17 is a sequence chart of a preparatory-stage process performedprior to the start of communications between transmission terminals;

FIG. 18 is a sequence chart of a process of narrowing relay apparatuses;

FIG. 19 is a flowchart of a process of narrowing the relay apparatuses;

FIG. 20 is a table of priority points calculated for the process ofnarrowing the relay apparatuses;

FIG. 21 is a sequence chart of a process of the transmission terminalselecting one of the relay apparatuses;

FIG. 22 is a flowchart of the process of the transmission terminalselecting one of the relay apparatuses;

FIG. 23 is a sequence chart of a process of transmitting and receivingvideo data and audio data between transmission terminals;

FIG. 24 illustrates a material managing table stored in a storage unit;

FIG. 25 is a functional block diagram of the external input apparatus;

FIG. 26 is a sequence chart of a process of causing the transmissionterminal on the other end of a video conference to display datadisplayed on the external input apparatus on one end;

FIG. 27 illustrates an example of a screen displayed by the externalinput apparatus on the one end of the video conference;

FIG. 28 is an example of a screen of the transmission terminal on theother end of the video conference; and

FIG. 29 is a flowchart of a process of installing a display dataacquiring unit in the external input apparatus.

BEST MODE FOR CARRYING OUT THE INVENTION Overall Structure of Embodiment

Embodiments of the present invention are described with reference to theattached drawings. FIG. 1 illustrates a transmission system 1 accordingto an embodiment. The transmission system may include a data providingsystem for transmitting content data from one transmission terminal toanother transmission terminal via a transmission managing system, and acommunication system for transmitting information or emotions amongplural transmission terminals via a transmission managing system. Thecommunication system may allow transmission of information or emotionsamong plural communication terminals (corresponding to “transmissionterminals”) via a communication managing system (corresponding to“transmission managing system”). Examples of the communication systeminclude television or video conference systems, videophone systems,voice conference systems, voice telephony systems, and PC (PersonalComputer) screen sharing systems.

In accordance with the present embodiment, a transmission system, atransmission managing system, and a transmission terminal are describedwith reference to a television or video conference system as an exampleof the communication system, a television or video conference managingsystem as an example of the communication managing system, and atelevision or video conference terminal as an example of thecommunication terminal. Thus, the transmission terminal and thetransmission managing system according to the embodiment may be appliedto not just a television or video conference system but also to acommunication system or a transmission system.

Referring to FIG. 1, the transmission system 1 includes pluraltransmission terminals 10 aa, 10 ab, . . . , 10 db, displays 120 aa, 120ab, . . . , 120 db for the transmission terminals 10 aa, 10 ab, . . . ,10 db, plural relay apparatuses 30 a, 30 b, 30 c, and 30 d, atransmission managing system 50, a program providing system 90, and amaintenance system 100.

In accordance with the present embodiment, any of the transmissionterminals 10 aa, 10 ab, . . . , 10 db may be referred to as “thetransmission terminal 10”. Any of the displays 120 aa, 120 ab, . . . ,120 db may be referred to as “the display 120”. Any of the relayapparatuses 30 a, 30 b, 30 c, and 30 d may be referred to as “the relayapparatus 30”.

The transmission terminal 10 may transmit or receive video data or audiodata to or from another transmission terminal 10. In accordance with thepresent embodiment, the video data may include a moving image or a stillimage, or both. The relay apparatus 30 relays video data and audio databetween plural transmission terminals 10. The transmission managingsystem 50 centrally manages the transmission terminal 10 and the relayapparatus 30.

An external input apparatus 40 is connected to the transmission terminal10 and transmits display data for displaying material data to thetransmission terminal 10. The “material data” may include data that isutilized by document creating software, spreadsheet software, orpresentation software.

Routers 70 a, 70 b, . . . , 70 f select optimum routes for the videodata and audio data. In accordance with the present embodiment, any ofthe routers (70 a, 70 b, . . . , 70 f) may be referred to as the router70″. The program providing system 90 includes a HD (Hard Disk; notillustrated) for storing a transmission terminal program for realizingvarious functions or units of the transmission terminal 10. Thetransmission terminal program may be transmitted to the transmissionterminal 10. The HD of the program providing system 90 also stores arelay apparatus program for realizing various functions or units of therelay apparatus 30. The relay apparatus program may be transmitted tothe relay apparatus 30. Further, the HD of the program providing system90 also stores a transmission managing program for realizing variousfunctions or units of the transmission managing system 50. Thetransmission managing program may be transmitted to the transmissionmanaging system 50.

The transmission terminal 10 aa, the transmission terminal 10 ab, therelay apparatus 30 a, and the router 70 a are communicatively connectedto each other via a LAN 2 a. The transmission terminal 10 ba, thetransmission terminal 10 bb, the relay apparatus 30 b, and the router 70b are communicatively connected to each other via a LAN 2 b. The LAN 2 aand the LAN 2 b are communicatively connected via a dedicated line tabincluding the router 70 c and are located in a predetermined area A. Thearea A may cover a country, such as Japan. In this case, the LAN 2 a maybe located in a local office, such as one in Tokyo; the LAN 2 b may beprovided in another local office, such as one in Osaka.

The transmission terminal 10 ca, the transmission terminal 10 cb, therelay apparatus 30 c, and the router 70 d are communicatively connectedvia a LAN 2 c. The transmission terminal 10 da, the transmissionterminal 10 db, the relay apparatus 30 d, and the router 70 e arecommunicatively connected via a LAN 2 d. The LAN 2 c and the LAN 2 d arecommunicatively connected via a dedicated line 2 cd including the router70 f and are located within a predetermined area B. The area B may coveranother country, such as the United States of America. In this case, theLAN 2 c may be located in a local office, such as one in New York; theLAN 2 d may be located in another local office, such as one inWashington D.C. The areas A and B are communicatively connected by theInternet 2 i via the routers 70 c and 70 f.

The transmission managing system 50 and the program providing system 90are communicatively connected with the transmission terminal 10 and therelay apparatus 30 via the Internet 2 i. The transmission managingsystem 50 and the program providing system 90 may be located in the areaA or B, or in another area.

In accordance with the present embodiment, the LAN 2 a, the LAN 2 b, thededicated line 2 ab, the Internet 2 i, the dedicated line 2 cd, the LAN2 c, and the LAN 2 d constitute a communication network 2.

In FIG. 1, a set of four numbers indicated below the transmissionterminal 10, the relay apparatus 30, the transmission managing system50, the router 70, and the program providing system 90 indicates an IPaddress according to IPv4 in a simplified way. For example, the IPaddress of the transmission terminal 10 aa is “1.2.1.3”. Preferably,IPv6 may be used instead of IPv4.

Hardware Structure of Embodiment

A hardware structure according to the present embodiment is described.In accordance with the present embodiment, when a delay is caused uponreception of image data at the transmission terminal 10 as a relayeddestination, the resolution of the image of the image data is varied bythe relay apparatus 30 before transmitting the image data to thetransmission terminal 10 as the relayed destination. FIG. 2 is aperspective view of the transmission terminal 10 according to thepresent embodiment. In the following description, the lengthwisedirection of the transmission terminal 10 is referred to as the X-axisdirection; a direction perpendicular to the X-axis direction in ahorizontal plane is referred to as the Y-axis direction; and a directionperpendicular to the X-axis direction and the Y-axis direction isreferred to as the Z-axis direction (vertical direction).

As illustrated in FIG. 2, the transmission terminal 10 includes a casing1100, an arm 1200, and a camera housing 1300. The casing 1100 has afront-side wall surface 1110 which includes an air-inlet surface (notillustrated) including plural air-inlet openings. The casing 1100 alsoincludes a rear-side wall surface 1120 that includes an exhaust surface1121 having plural exhaust openings. Thus, outside air to the front ofthe transmission terminal 10 may be collected via the air-inlet surface(not illustrated) by operating a cooling fan (not illustrated) providedin the casing 1100 and then let out to the rear of the transmissionterminal 10 via the exhaust surface 1121. The casing 1100 has aright-side wall surface 1130 having a sound-pickup opening 1131 viawhich sound, such as voice or noise, can be picked up by a built-inmicrophone 114, which will be described later.

An operating panel 1150 is formed on an upper surface of the casing 1100on the side of the right-side wall surface 1130. The operating panel1150 may include plural operating buttons 108 a through 108 e, a powerswitch 109, an alarm lamp 119, and an audio output surface 1151. Theaudio-output surface 1151 may include plural audio output openings forletting out sound from a built-in speaker 115 (see FIG. 3). On the sideof a left-side wall surface 1140 of the casing 1100, there is formed acontainer portion 1160 which may include cavities for accommodating thearm 1200 and the camera housing 1300. In the right-side wall surface1130 of the casing 1100, there are formed plural connecting openings1132 a through 1132 c for electrical connection of cables to an externaldevice connecting I/F 118. In the left-side wall surface 1140 of thecasing 1100, there is formed a connecting opening (not illustrated) forelectrical connection of a cable 120 c from a display 120 to theexternal device connecting I/F 118. In the following description, any ofthe operating buttons 108 a through 108 e may be referred to as theoperating button 108″. Any of the connecting openings 1132 a through1132 c may be referred to as the connecting opening 1132″.

The arm 1200 may be attached to the casing 1100 via a torque hinge 1210allowing the arm 1200 to be rotated up or down with respect to thecasing 1100 in a range of a tilt angle θ1 of 135°, for example. FIG. 2illustrates the arm 1200 rotated up to the tilt angle θ1 of 90°.

The camera housing 1300 houses the built-in camera 1021 with which anobject, such as a person, a document, or a room, may be imaged. Thecamera housing 1300 is attached to the arm 1200 via a torque hinge 1310allowing the camera housing 1300 to be rotated vertically andhorizontally with respect to the arm 1200. Specifically, the cameralhousing 1300 may be rotated in a range of a panning angle θ2 of ±180°and a range of a tilt angle θ3 of ±45° from the 0° position of thecamera housing 1330 illustrated in FIG. 2.

The exteriors of the relay apparatus 30, the managing system 50, and theprogram providing system 90 are not illustrated because they may besimilar to those of general servers or computers.

FIG. 3 is a block diagram illustrating a hardware structure of thetransmission terminal 10. As illustrated, the transmission terminal 10includes a CPU (Central Processing Unit) 101 for controlling theoperation of the transmission terminal 10 as a whole; a ROM (Read OnlyMemory) 102 which may store the transmission terminal program; a RAM(Random Access Memory) 103 which may be used as a work area for the CPU101; a flash memory 104 which may store various data such as video dataand audio data; a SSD (Solid State Drive) 105 which may control readingor writing of various data from or into the flash memory 104 under thecontrol of the CPU 101; a media drive 107 for controlling the reading orwriting (i.e., storage) of data from or into a recording medium 106 suchas a flash memory; an operating button 108 which may be operated whenselecting an address of the transmission terminal 10; a power switch 109for turning on or off the transmission terminal 10; a network I/F 111for transmitting data by utilizing the communication network 2; a CCD(Charge Coupled Device) 112 for imaging an object under the control ofthe CPU 101; an imaging element I/F 113 for controlling the operation ofthe camera 112; a microphone 114 for picking up sound; a speaker 115 forproviding an audio output; an audio input/output I/F 116 for processingthe input and output of an audio signal between the microphone 114 andthe speaker 115 under the control of the CPU 101; a display I/F 117 fortransmitting video data to the external display 120; an external unitI/F 118 for transmitting or receiving various data to or from theexternal apparatus; an alarm lamp 119 for indicating abnormality in anyof the functions of the terminal 10; and a bus line 110, which mayinclude an address bus and a data bus, for electrically connecting thevarious constituent elements as illustrated in FIG. 3.

The display 120, which may include an LCD or organic EL(electroluminescence) display unit, displays an image of an object oroperating icons. The display 120 is connected to the display I/F 117 viathe cable 120 c. The cable 120 c may include cables for an analog RGB(VGA) signal, a component video signal, a HDMI (High-DefinitionMultimedia Interface) signal, or a DVI (Digital Video Interactive)signal, for example. The camera 112 may include a lens and a solid-stateimage sensing element for converting light into electric charges so asto obtain an electric signal of an object image (picture). Thesolid-state image sensing element may include a CMOS (ComplementaryMetal Oxide Semiconductor) or a CCD (Charge Coupled Device).

To the external device connecting I/F 118, external devices, such as anexternal camera, an external microphone, or an external speaker may beelectrically connected via a USB (Universal Serial Bus) cable insertedinto the connecting opening 1132 of the casing 1100 illustrated in FIG.2. When the external camera is connected, the external camera may beactivated with priority over the built-in camera 112 under the controlof the CPU 101. Similarly, when the external microphone or the externalspeaker is connected, they may be activated with priority over thebuilt-in microphone 114 or the built-in speaker 115, respectively, underthe control of the CPU 101.

The recording medium 106 may be freely attached to or detached from thetransmission terminal 10. The flash memory 104 is merely an example of anon-volatile memory. Any non-volatile memory, such as an EEPROM(Electrically Erasable and Programmable ROM), capable of reading orwriting data under the control of the CPU 101 may be used. Thetransmission terminal program may be recorded in a computer-readablerecording medium, such as the recording medium 106, in a file of aninstallable or executable format.

FIG. 4 illustrates a hardware structure of the transmission managingsystem 50 according to the present embodiment. The transmission managingsystem 50 includes a CPU 201 for controlling the operation of thetransmission managing system 50 as a whole; a ROM 202 storing thetransmission managing program; a RAM 203 used as a work area for the CPU201; a HD (Hard Disk) 204 storing various data; a HDD (Hard Disk Drive)205 controlling the reading or writing of various data from or into theHD 204 under the control of the CPU 201; a media drive 207 controllingthe reading or writing (storing) of data from or into the recordingmedium 206 which may include a flash memory; a display 208 displayingvarious information items such as a cursor, a menu, a window,characters, or images; a network I/F 209 for data transmission utilizingthe communication network 2; a keyboard 211 having plural keys forinputting characters, values, or various instructions; a mouse 212 forselecting or activating various instructions, selecting a processingtarget, or moving the cursor; a CD-ROM drive 214 for controlling thereading or writing of data from or into the CD-ROM (Compact Disc ReadOnly Memory) 213 as an example of a detachable recording medium; anexternal unit I/F 215 for transmitting or receiving information to orfrom the external apparatus; and a bus line 210 which may include anaddress bus and a data bus for electrically connecting the variousconstituent elements to one another, as illustrated in FIG. 4.

The transmission managing program may be recorded in a computer-readablerecording medium such as the recording medium 206 or the CD-ROM 213 in afile of an installable or executable format for distribution. Theexternal input apparatus 40 may have a hardware structure similar tothat of the transmission managing system 50. However, the ROM 202 storesan external input apparatus program for controlling the external inputapparatus 40. The external input apparatus program may be recorded inthe recording medium 206 or the CD-ROM 213 in a file of an installableor executable format for distribution.

The relay apparatus 30 may have a hardware structure similar to that ofthe transmission managing system 50. However, the ROM 202 stores a relayapparatus program for controlling the relay apparatus 30. The relayapparatus program may be recorded in the recording medium 206 or theCD-ROM 213 in a file of an installable or executable format fordistribution.

The program providing system 90 may have a hardware structure similar tothat of the transmission managing system 50. However, the ROM 202 storesa program providing program for controlling the program providing system90. The program providing program may be recorded in the recordingmedium 206 or the CD-ROM 213 in a file of an installable or executableformat for distribution.

The maintenance system 100 may include a computer configured to maintainor manage the terminal 10, the relay apparatus 30, the managing system50, and/or the program providing system 90. For example, when themaintenance system 100 is provided in one country while the terminal 10,the relay apparatus 30, the managing system 50, or the program providingsystem 90 is provided in another country, the maintenance system 100 mayperform a maintenance operation for maintaining or managing at least oneof the terminal 10, the relay apparatus 30, the managing system 50, theauthentication system 80, and the program providing system 90 via thecommunication network 2. The maintenance system 100 may maintain ormanage information of a model type number, a manufacturing number, asales destination, maintenance and inspection, or a failure history ofat least one of the terminal 10, the relay apparatus 30, the managingsystem 50, and the program providing system 90 without using thecommunication network 2.

The program providing system 90 and the maintenance system 100 may havea hardware structure similar to that of the managing system 50. The HD204 may record the program providing program for controlling the programproviding system 90. The program providing program may be recorded in acomputer-readable recording medium such as the recording medium 206 orthe CD-ROM 213 in a file of an installable or executable format fordistribution. Alternatively, the program providing program may be storedin the ROM 202 instead of the HD 204. The computer-readable recordingmedium may include detachable recording media such as a CD-R (CompactDisc Recordable), a DVD (Digital Versatile Disk), and a Blu-ray disc.

Functional Structure of Embodiment

FIG. 5 is a functional block diagram of the transmission system 1according to the present embodiment. In FIG. 5, the transmissionterminal 10, the relay apparatus 30, and the transmission managingsystem 50 are connected to one another via the communication network 2in a data-communicative manner. The external input apparatus 40 isconnected to the transmission terminal 10 in a data-communicativemanner. A functional block diagram of the external input apparatus 40constituting the transmission system 1 according to the presentembodiment is illustrated in FIG. 24. The program providing system 90 ofFIG. 1 is not illustrated in FIG. 5 because the program providing system90 is not directly relevant to communications for a video conference.

Functional Structure of Transmission Terminal

Referring to FIG. 5, the transmission terminal 10 includes atransmitting/receiving unit 11; an operating input receiving unit 12; alogin request unit 13; an imaging unit 14 a; an image display controlunit 14 b; an audio input unit 15 a; an audio output unit 15 b; aselection processing unit 16; a delay detecting unit 17; an externalinformation transmitting/receiving unit 18; and a storage/readprocessing unit 19. The functions of these units may be provided byoperating the constituent elements illustrated in FIG. 3 in accordancewith an instruction from the CPU 201 according to a program stored inthe ROM 202. The transmission terminal 10 also includes a storage unit1000 which may include the SSD 105 illustrated in FIG. 3.

Functional Units of Transmission Terminal

The various portions of the transmission terminal 10 are described indetail. The transmitting/receiving unit 11, which may be realized by thenetwork I/F 111 of FIG. 3, transmits or receives various data(information) to or from another terminal, apparatus, or system via thecommunication network 2. The operating input receiving unit 12, whichmay be realized by the operating button 108 and the power switch 109 ofFIG. 3, receives various inputs from a user. For example, when the userturns on the power switch 109 of FIG. 3, the operating input receivingunit 12 of FIG. 5 receives a power-on signal and turns on thetransmission terminal 10. The login request unit 13 may be realized inaccordance with an instruction from the CPU 101 of FIG. 3. In responseto the reception of the power-on signal, the login request unit 13 mayautomatically transmit login request information and a current IPaddress of the transmission terminal 10 ab to the transmission managingsystem 50 via the transmitting/receiving unit 11 and the communicationnetwork 2.

Still referring to FIG. 5, the imaging unit 14 a, which may be realizedby the camera 112 and the imaging element I/F 113 of FIG. 3, images anobject and outputs resultant video data. The image display control unit14 b, which may be realized by the display I/F 117 of FIG. 3, maycontrol the transmission of video data to the external display 120. Theaudio input unit 15 a, which may be realized by the microphone 114 andthe audio input/output I/F 116 of FIG. 3, may convert a user's voiceinto an audio signal, thereby outputting audio data. The audio outputunit 15 b, which may be realized by the speaker 115 and the audioinput/output I/F 116 of FIG. 3, may convert the audio signal into actualsound, thus producing an audio output.

The selection processing unit 16, in order to perform a final narrowingprocess for narrowing the plural relay apparatuses 30 down to oneselected relay apparatus 30, may realize a measuring unit 16 a, acalculating unit 16 b, and a selecting unit 16 c in response to aninstruction from the CPU 101 of FIG. 3. The measuring unit 16 a measuresa receive date/time of reception of pre-transmit information by thetransmitting/receiving unit 11 each time the pre-transmissioninformation is received by the transmitting/receiving unit 11 as will bedescribed later. The calculating unit 16 b calculates a required timebetween the transmission and reception of the pre-transmit informationbased on a difference between the receive time measured by the measuringunit 16 a and the transmit date/time included in the pre-transmitinformation, for each item of the pre-transmit information of which thereceive date/time is measured by the measuring unit 16 a. The selectingunit 16 c selects the one of the relay apparatuses 30 that has relayedthe pre-transmission information with the minimum of the required timescalculated by the final calculating unit 16 b.

The delay detecting unit 17, which may be realized in response to aninstruction from the CPU 101 of FIG. 3, may detect a delay time (ms) ofthe video data or audio data sent from the other transmission terminal10 via the relay apparatus 30. The external informationtransmitting/receiving unit 18 may transmit or receive data to or fromthe external apparatus 40 using the external unit I/F 215. Thestorage/read processing unit 19, which may be provided by the SSD 105 ofFIG. 3, may process the reading or writing of various data from or intothe storage unit 1000. The storage unit 1000 may store a terminal IDidentifying the transmission terminal 10 and a corresponding password, arelay apparatus ID identifying the relay apparatus 30 via which videodata, audio data, and various data may be transmitted, and an IP addressof a destination terminal. The storage unit 1000 may also store adisplay data acquiring unit 451 and a display data transmitting unit 452that may be transmitted to the external input apparatus 40 and operatedtherein. The display data acquiring unit 451 enables the acquisition ofdisplay data by the external input apparatus 40. The display datatransmitting unit 452 enables the transmission of the display dataacquired by the display data acquiring unit 451 to the transmissionterminal 10. The display data may include video data of an imagedisplayed on a screen of a display apparatus in JPEG (Joint PhotographicExperts Group) or Bitmap format, or a drawing command of the image inGDI (Graphics Device Interface) format.

The terminal ID and the relay apparatus ID, which will be describedlater, may include various information items uniquely identifying thetransmission terminal 10 and the relay apparatus 30, respectively. Theidentifying information may include a language, a character, a sign, ora symbol. At least two of these information items, i.e., a language, acharacter, a sign, and a symbol may be used in combination. In thefollowing description, the transmission terminal 10 as a request sourcethat requests the start of a video conference is referred to as the“request source terminal 10A”, while the transmission terminal 10 towhich the request is sent may be referred to as the “destinationterminal 10B”.

Material Managing Table

The storage unit 4000 includes a material managing DB 4001 which may bein the form of a material managing table illustrated in FIG. 24. Thematerial managing table manages the name and size of a material, thename of application software used for creating the material, thedate/time of last update of the material, and material data inassociation with one another.

Functional Structure of External Input Apparatus

The external input apparatus 40, as illustrated in FIG. 24, includes atransmitting/receiving unit 41, a connection detecting unit 42, aninstall determination unit 43, a program acquiring unit 44, an operatinginput receiving unit 46, a display control unit 47, a mount unit 48, anda storage/read processing unit 49. These units may be provided byoperating the constituent elements illustrated in FIG. 4 in accordancewith an instruction from the CPU 201 according to a program stored inthe ROM 202. The external input apparatus 40 also includes a storageunit 4000 which may be provided by the HDD 205 of FIG. 4. The externalinput apparatus 40 may include an operating system (OS), such as aMicrosoft Windows OS™ available from Microsoft Corp., which may providethe function of executing a program upon connection with anotherapparatus.

Material Managing Table

The storage unit 400 may include a material managing DB 4001 which maybe in the form of a material managing table (not illustrated). Thematerial managing table may manage a material name, a material size, aname of an application used for creating the material, the date/time ofthe last update of the material, and material data in association withone another.

Functional Units of External Input Apparatus

The various units of the external input apparatus 40 are described. Thetransmitting/receiving unit 41, which may be realized by the network I/F209 of FIG. 4, may process the transmission and reception of variousdata (information) to or from the transmission terminal 10. Theconnection detecting unit 42 may detect when the transmission andreception of data to or from the external unit is enabled by theexternal unit input/output I/F 215. The install determination unit 43may determine whether the display data acquiring unit 451 or the displaydata transmitting unit 452 is installed in the external input apparatus40. The program acquiring unit 44 may acquire, from the storage unit1000 of the transmission terminal 10 connected via thetransmitting/receiving unit 41, the display data acquiring unit 451 andthe display data transmitting unit 452, and install them. The operatinginput receiving unit 46 may receive an input based on a user operation.The display control unit 47 may cause an image read by the storage/readprocessing unit 49 to be displayed on the display apparatus 400. Themount unit 48 may mount storage units of various apparatuses connectedto the external input apparatus 40. The storage/read processing unit 49,which may be provided by the HDD 205 of FIG. 4, may process the storingof various data in the storage unit 4000 or the reading of various datafrom the storage unit 4000. The storage unit 4000 may store the materialdata and the like.

Functional Structure of Relay Apparatus

Referring to FIG. 5, the relay apparatus 30 includes atransmitting/receiving unit 31, a status detecting unit 32, a dataquality confirming unit 33, a modified quality managing unit 34, a dataquality modifying unit 35, and a storage/read processing unit 39. Theseunits may be realized by operating the constituent elements illustratedin FIG. 4 in accordance with an instruction from the CPU 201 accordingto a program stored in the ROM 202. The relay apparatus 30 includes astorage unit 3000 which may be provided by the HD 204 illustrated inFIG. 4.

Modified Quality Managing Table

The storage unit 3000 includes a modified quality managing DB 3001 whichmay be in the form of a modified quality managing table illustrated inFIG. 7. The modified quality managing table of FIG. 7 manages the imagequality of video data relayed by the relay apparatus 30 to thetransmission terminal 30 (relayed destination) in association with theIP address of the transmission terminal 30.

The resolution of video data handled according to the present embodimentis described. FIG. 6A illustrates a low-resolution image as a base imagehaving 160 pixels horizontally times 120 pixels vertically. FIG. 6Billustrates an intermediate-resolution image having 320 pixelshorizontally times 240 pixels vertically. FIG. 6C illustrates ahigh-resolution image having 640 pixels horizontally times 480 pixelsvertically. When a narrow-band route is used, the low-quality video dataof the low-resolution image may be relayed. When the band is relativelywide, intermediate-quality video data including the video data of thelow-resolution video (base image) and the video data of theintermediate-resolution image may be relayed. When the band is verywide, high-quality video data including the low-resolution video data(base image quality), the intermediate-resolution video data, and thehigh-resolution video data may be relayed. For example, in the modifiedquality managing table of FIG. 7, when the relay apparatus 30 relaysvideo data to the destination terminal 10 db with the IP address“1.3.2.4”, the image quality of the relayed video data is“high-quality”.

Functional Units of Relay Apparatus

The functional structure of the relay apparatus 30 is described indetail. Reference may also be made to the constituent elements of FIG. 3for realizing the units of the relay apparatus 30.

Referring to FIG. 5, the transmitting/receiving unit 31, which may berealized by the network I/F 209 of FIG. 4, may transmit or receivevarious data (information) to or from another terminal, apparatus, orsystem via the communication network 2. The status detecting unit 32,which may be realized in accordance with an instruction from the CPU 201of FIG. 4, may detect an operating status of the relay apparatus 30. Theoperating status may include “online”, “offline”, and “failure”.

The data quality confirming unit 33, which may be realized in accordancewith an instruction from the CPU 201 of FIG. 4, may search the modifiedquality managing table (see FIG. 7) by using the IP address of thedestination terminal 10B as a search key, and extract the image qualityof corresponding relayed video data, thus confirming the image qualityof the relayed video data. The modified quality managing unit 34, whichmay be realized in accordance with an instruction from the CPU 201 ofFIG. 4, may modify the contents of the modified quality managing DB 3001based on quality information sent from the transmission managing system50, as will be described below.

For example, during a video conference in which high-quality video datais transmitted or received between the request source terminal 10 aawith the terminal ID “01 aa” and the destination terminal 10 db with theterminal ID “01 db”, the terminal 10 bb (request source) and theterminal 10 ca (destination) may start another video conference via thecommunication network 2, resulting in a delay in receiving video data bythe destination terminal 10 db. In this case, the relay apparatus 30 mayneed to lower the image quality of the video data that has been relayedfrom high quality to intermediate quality. In such a case, the contentsof the modified quality managing DB 3001 may be modified based on thequality information indicating the intermediate image quality, so thatthe image quality of the video data relayed by the relay apparatus 30can be lowered from high-quality to intermediate quality.

The data quality modifying unit 35, which may be realized in response toan instruction from the CPU 201 of FIG. 4, may modify the image qualityof the video data sent from the terminal 10 as the transmitting source,based on the modified content of the modified quality managing DB 3001.The storage/read processing unit 39, which may be realized by the HDD205 of FIG. 4, may process the writing or reading of various data intoor from the storage unit 3000.

Functional Structure of Transmission Managing System

Still referring to FIG. 5, the transmission managing system 50 includesa transmitting/receiving unit 51, a terminal authentication unit 52, astatus managing unit 53, a terminal extracting unit 54, a terminalstatus acquiring unit 55, a narrowing unit 56, a session managing unit57, a quality determining unit 58, a storage/read processing unit 59,and a delay time managing unit 60. These units may be realized byoperating the constituent elements of FIG. 4 in accordance with aninstruction from the CPU 201 according to a program stored in the ROM202. The transmission managing system 50 includes a storage unit 5000which may be provided by the HD 204 of FIG. 4.

Relay Apparatus Managing Table

Referring to FIG. 5, the storage unit 5000 includes a relay apparatusmanaging DB 5001 which may be in the form of a relay apparatus managingtable as illustrated in FIG. 8. The relay apparatus managing tablestores and manages the operating status of the relay apparatus 30, thereceive date/time of reception of status information indicating theoperating status by the transmission managing system 50, the IP addressof the relay apparatus 30, and the maximum data transmission rate (Mbps)of the relay apparatus 30 in association with the relay apparatus ID ofthe relay apparatus 30. For example, the relay apparatus managing tableof FIG. 8 indicates that, for the relay apparatus 30 a with the relayapparatus ID “111 a”, the operating status is “online”, that the statusinformation was received by the transmission managing system 50 on Nov.10, 2009 at 13:00 p.m., the IP address of the relay apparatus 30 a is“1.2.1.2”, and the relay apparatus 30 a has a maximum data transmissionrate of 100 Mbps.

Terminal Authentication Managing Table

The storage unit 5000 also includes a terminal authentication managingDB 5002 which may be in the form of a terminal authentication managingtable as illustrated in FIG. 9. The terminal authentication managingtable manages a password in association with the terminal ID of each ofthe transmission terminals 10 managed by the transmission managingsystem 50. For example, the transmission terminal 10 aa with theterminal ID “01 aa” is associated with the password “aaaa”.

Terminal Managing Table

The storage unit 5000 also includes a terminal managing DB 5003 whichmay be in the form of a terminal managing table as illustrated in FIG.10. The terminal managing table manages the operating status of thetransmission terminal 10, the receive date/time of reception of thelogin request information by the transmission managing system 50, andthe IP address of the transmission terminal 10 in association with theterminal ID of the transmission terminal 10. For example, the terminalmanaging table indicates that, for the transmission terminal 10 aa withthe terminal ID “01 aa”, the operating status is “online”, that thelogin request information was received by the transmission managingsystem 50 on Nov. 10, 2009 at 13:40 p.m., and that the IP address of thetransmission terminal 10 aa is “1.2.1.3”.

Destination List Managing Table

The storage unit 5000 includes a destination list managing DB 5004 whichmay be in the form of a destination list managing table as illustratedin FIG. 11. The destination list managing table manages the terminal IDsof all candidates for the destination terminal 10B in association withthe terminal ID of the request source terminal 10A that requests thestart of a video conference. For example, the terminal IDs of thecandidates (transmission terminals) for the destination terminal 10B towhich a request for the start of a video conference may be sent from therequest source terminal 10 aa with the terminal ID “01 aa” are theterminal IDs “01 ab”, “01 ba”, and “01 db”. The candidates for thedestination terminal 10B may be updated by addition or deletion inresponse to an addition or deletion request from the request sourceterminal 10A to the transmission managing system 50.

Session Managing Table

The storage unit 5000 also includes a session managing DB 5005 which maybe in the form of a session managing table as illustrated in FIG. 12.The session managing table manages, in association with the selectionsession ID used for executing a session for selecting the relayapparatus 30, the relay apparatus ID of the relay apparatus 30 used forrelaying the video data or audio data; the terminal ID of the requestsource terminal 10A; the terminal ID of the destination terminal 10B;the delay time (ms) in receiving the video data by the destinationterminal 10B; and the receive date/time of reception of delayinformation indicating the delay time by the transmission managingsystem 50 from the destination terminal 10B.

For example, the session managing table of FIG. 12 indicates that therelay apparatus 30 a (with the relay apparatus ID “111 a”) that isselected in a session executed by using the selection session ID “se1”relays video data and audio data between the request source terminal 10aa with the terminal ID “01 aa” and the destination terminal 10 db withthe terminal ID “01 db”, and that the delay time of the video data uponreception at the destination terminal 10 db at 14:00 p.m. on Nov. 10,2009, is 200 ms. Preferably, when a video conference is conductedbetween the two transmission terminals 10, the receive date/time of thedelay information may be managed based on the delay informationtransmitted from the request source terminal 10A, instead of thedestination terminal 10B. However, when a video conference is conductedamong three or more transmission terminals 10, the receive date/time ofthe delay information may be managed based on the delay informationtransmitted from the transmission terminal 10 on the receiving end ofvideo data and audio data.

Address Priority Managing Table

Further, the storage unit 5000 includes a priority managing DB 5006which may be in the form of an address priority managing table asillustrated in FIG. 13. The illustrated address priority managing tablemanages the address priority by allocating various address prioritypoints depending on the number of the “same” or “different” sections ofthe four sections of the dot address of the general IP address schemeaccording to IPv4.

For example, the address priority managing table of FIG. 13 indicatesthat, in the case of the IP address having the corresponding values(“same”) in the three upper sections of the dot address, the addresspriority is “5”. In the case of the IP address having correspondingvalues in the upper two sections of the dot address, the addresspriority is “3”. In this case, correspondence (i.e., whether “same” or“different”) of the value in the lowest dot address section isirrelevant to the priority point. In the case of the IP address having acorresponding value only in the upper-most section of the dot address,with the value in the second upper-most section not corresponding, theaddress priority is “1”. In this case, correspondence of the values ofthe third highest section and the lowest section of the dot address isirrelevant to the priority point. In the case of the IP address wherethe value of the highest section of the dot address is notcorresponding, the address priority is “0”. In this case, correspondenceof the values of the second-highest, the third-highest, and the lowestsections of the dot address is irrelevant to the priority point.

Transmission Rate Priority Managing Table

The priority managing DB 5006 in the storage unit 5000 may include atransmission rate priority managing table illustrated in FIG. 14. Thetransmission rate priority managing table manages a transmission ratepriority depending on the value of the maximum data transmission rate(Mbps) of the relay apparatus 30. Specifically, the transmission ratepriority has higher points for higher maximum data transmission rates.For example, the transmission rate priority managing table of FIG. 14indicates that, when the maximum data transmission rate of the relayapparatus 30 is 1000 Mbps or higher, the transmission rate prioritypoint is “5”. When the maximum data transmission rate of the relayapparatus 30 is equal to or more than 100 Mbps and less than 1000 Mbps,the transmission rate priority point is “3”. When the maximum datatransmission rate of the relay apparatus 30 is equal to or more than 10Mbps and less than 100 Mbps, the transmission rate priority point is“1”. When the maximum data transmission rate of the relay apparatus 30is less than 10 Mbps, the transmission rate priority point is “0”.

Quality Managing Table

The storage unit 5000 further includes a quality managing DB 5007 whichmay be in the form of a quality managing table illustrated in FIG. 15.The illustrated quality managing table manages the image quality of thevideo data relayed by the relay apparatus 30 in association with thedelay time (ms) of the video data in the request source terminal 10A orthe destination terminal 10B.

Functional Units of Transmission Managing System

Still referring to FIG. 5, the functional units of the transmissionmanaging system 50 are described in detail. Reference is also made tothe constituent elements of FIG. 4 for realizing the units of thetransmission managing system 50.

The transmitting/receiving unit 51, which may be provided by the networkI/F 209 of FIG. 4, may transmit or receive various data (information) toor from another terminal, apparatus, or system via the communicationnetwork 2. The terminal authentication unit 52 may search the terminalauthentication managing DB 5002 in the storage unit 5000 by using theterminal ID and password included in the login request informationreceived via the transmitting/receiving unit 51 as search keys. Based onwhether corresponding terminal ID and password are stored in theterminal authentication managing DB 5002, terminal authentication isperformed. The status managing unit 53, in order to manage the operatingstatus of the request source terminal 10A that has transmitted a loginrequest, stores and manages the terminal ID of the request sourceterminal 10A, the operating status of the request source terminal 10A,the receive date/time of reception of the login request information bythe transmission managing system 50 and the IP address of the requestsource terminal 10A in association with one another in the terminalmanaging table (see FIG. 11).

The terminal extracting unit 54 searches the destination list managingtable (see FIG. 11) by using the terminal ID of the request sourceterminal 10A that made the login request as a key, and reads theterminal IDs of candidates for the destination terminal 10B that cancommunicate with the request source terminal 10A. The terminalextracting unit 54 also searches the destination list managing table(see FIG. 11) by using the terminal ID of the request source terminal10A that made the login request as a key, and extracts the terminal IDof another request source terminal 10A that has registered the terminalID of the request source terminal 10A as a candidate for the destinationterminal 10B.

The terminal status acquiring unit 55, by using the terminal IDs of thecandidates for the destination terminal 10B extracted by the terminalextracting unit 54 as a search key, searches the terminal managing DBtable (see FIG. 10), and reads the operating status of each of theterminal IDs extracted by the terminal extracting unit 54. In this way,the terminal status acquiring unit 55 can acquire the operating statusof each candidate for the destination terminal 10B that can communicatewith the request source terminal 10A. Further, the terminal statusacquiring unit 55 searches the terminal managing table (see FIG. 10) byusing the terminal ID extracted by the terminal extracting unit 54 as asearch key in order to acquire the operating status of the requestsource terminal 10A.

The narrowing unit 56 performs a primary narrowing process prior to thefinal narrowing process in order to support the final narrowing processfor narrowing plural relay apparatuses 30 down to one selected relayapparatus 30. The narrowing unit 56 includes a selection session IDgenerating unit 56 a, a terminal IP address extracting unit 56 b, aprimary selecting unit 56 c, and a priority determining unit 56 d. Theselection session ID generating unit 56 a generates a selection sessionID used for a session for selecting the relay apparatus 30. The terminalIP address extracting unit 56 b, based on the terminal ID of the requestsource terminal 10A included in the start requesting informationtransmitted from the request source terminal 10A, and the terminal ID ofthe destination terminal 10B, searches the terminal managing table (seeFIG. 10) in order to extract the IP address of each of the correspondingtransmission terminals 10. The primary selecting unit 56 c selects thefinally narrowed relay apparatus 30 by selecting the relay apparatus IDof the relay apparatus 30 whose operating status is “online” among therelay apparatuses 30 managed by the relay apparatus managing table (seeFIG. 8).

The primary selecting unit 56 c, based on the IP address of the requestsource terminal 10A and the IP address of the destination terminal 10Bthat have been extracted by the terminal IP address extracting unit 56b, searches the relay apparatus managing table (see FIG. 8) in order todetermine whether the dot address of the IP address of each of the relayapparatuses 30 is the same as or different from the dot address of theIP address of each of the request source terminal 10A and thedestination terminal 10B. Further, the primary selecting unit 56 cnarrows the relay apparatuses 30 down to two relay apparatuses 30 havingthe highest points in terms of integrated points integrating, for eachrelaying apparatus, the higher of the address priority points of thetransmission terminals 10 and the transmission rate priority points.While in accordance with the present embodiment the two relayapparatuses 30 having higher points are selected, this is merely anexample; three of more relay apparatuses 30 having higher points may beselected as long as the relay apparatuses 30 can be narrowed down.

The priority determining unit 56 d, by referring to the prioritymanaging table (see FIG. 13), determines the address priority points foreach of the relay apparatuses 30 investigated by the primary selectingunit 56 c. The priority determining unit 56 d also, based on the maximumdata transmission rate of each of the relay apparatuses 30 managed inthe relay apparatus managing table (see FIG. 8), searches the prioritymanaging table (see FIG. 14) in order to determine the transmission ratepriority points for each of the relay apparatuses 30 narrowed down bythe primary selecting unit 56 c.

The session managing unit 57 stores the selection session ID generatedby the selection session ID generating unit 56 a, the terminal ID of therequest source terminal, and the terminal ID of the destination terminalin association with one another in the session managing table of thestorage unit 5000 (see FIG. 12). The session managing unit 57 alsostores the relay apparatus ID of the relay apparatus 30 finally selectedby the selecting unit 16 c of the transmission terminal 10 in thesession managing table (see FIG. 12) for each selection session ID.

Referring to FIG. 5, the quality determining unit 58 searches thequality managing table (see FIG. 15) by using the delay time as a searchkey in order to extract the image quality of the video data, thusdetermining the image quality of the video data to be relayed by therelay apparatus 30. The storage/read processing unit 59, which may beprovided by the HDD 205 of FIG. 4, may process the writing or reading ofvarious data into or from the storage unit 5000. The delay time managingunit 60 searches the terminal managing table (see FIG. 10) by using theIP address of the destination terminal 10B as a search key in order toextract the corresponding terminal ID. Further, the delay time managingunit 60 stores the delay time indicated by the delay information in adelay time field portion of a record including the extracted terminal IDin the session managing table (FIG. 12).

Processes and Operation

With reference to FIGS. 16 through 23 and FIGS. 26 through 29, aprocessing method performed in the transmission system 1 according tothe present embodiment is described. FIG. 16 is a sequence chart of aprocess of managing the status information transmitted from the relayapparatus 30 to the transmission managing system 1. FIG. 17 is asequence chart of a process in a preparatory stage prior to the start ofcommunications among plural transmission terminals 10. FIG. 18 is asequence chart of a process of narrowing the relay apparatuses 30. FIG.19 is a flowchart of the process of narrowing the relay apparatuses 30.FIG. 20 is a table illustrating how the points are calculated during theprocess of narrowing the relay apparatuses 30. FIG. 21 is a sequencechart of a process in which the transmission terminal 10 selects therelay apparatus 30. FIG. 22 is a flowchart of the process in which thetransmission terminal 10 selects the relay apparatus 30. FIG. 23 is asequence chart of a process in which video data and audio data aretransmitted and received between the transmission terminals 10. FIG. 26is a sequence chart of a process of causing the transmission terminal 10on the opposite end of a conference to display the display datadisplayed on the external input apparatus 40 on one end of theconference. FIG. 27 illustrates an example of a screen displayed by theexternal input apparatus 40. FIG. 28 illustrates an example of a screenfor displaying video data and display data on the transmission terminal10 on the opposite end. FIG. 29 is a flowchart of a process ofinstalling the display data acquiring unit in the external inputapparatus.

Referring to FIG. 16, a process of managing the status information ofthe relay apparatus 30 transmitted from the relay apparatus 30 to thetransmission managing system 50 is described. In the relay apparatus 30,the status detecting unit 32 illustrated in FIG. 5 detects the operatingstatus of the relay apparatus 30 at regular intervals (S1-1 throughS1-4). In order to enable the transmission managing system 50 to managethe operating status of the relay apparatus 30 in real time, thetransmitting/receiving unit 31 of the relay apparatus 30 transmits thestatus information to the transmission managing system 50 at regularintervals via the communication network 2 (steps S2-1 through S2-4). Thestatus information may include the relay apparatus ID of the relayapparatus 30 and the operating status of the corresponding relayapparatus 30. In accordance with the present embodiment, it is assumedthat the relay apparatuses 30 a, 30 b, and 30 d are operating normallyand in the “online” status but the relay apparatus 30 c, whileoperating, is in the “offline” status due to a problem in the programfor performing the relaying operation of the relay apparatus 30 c.

In the transmission managing system 50, the status informationtransmitted from the relay apparatus 30 is received by thetransmitting/receiving unit 51. The transmission managing system 50stores and manages the status information in the relay apparatusmanaging table of the storage unit 5000 (see FIG. 8) in association withthe relay apparatus ID, via the storage/read processing unit 59 (stepsS3-1 through S3-4). Thus, the operating status of “online”, “offline”,or “failure” is stored and managed in the relay apparatus managing tableof FIG. 8, in association with the relay apparatus ID. At this time, thereceive date/time of reception of the status information by thetransmission managing system 50 is also stored and managed inassociation with the relay apparatus ID. In the absence of transmissionof the status information from the relay apparatus 30, the fields of thecorresponding record of the relay apparatus managing table of FIG. 8 forthe operating status and the receive date/time may be left blank.Alternatively, the operating status and the receive date/time for theprevious reception may be indicated in the fields.

Referring to FIG. 17, a process in the preparatory stage prior to thestart of communications between the transmission terminal 10 aa and thetransmission terminal 10 db is described. First, a user turns on thepower switch 109 of FIG. 3, and then the operating input receiving unit12 of FIG. 5 turns on the transmission terminal 10 aa (step S21) inresponse to a power-on signal. In response, the login request unit 13automatically transmits login request information indicating a loginrequest to the transmission managing system 50 from thetransmitting/receiving unit 11 via the communication network 2 (stepS22). The login request information may include the terminal IDidentifying the transmission terminal 10 aa as a requesting source and apassword. The terminal ID and the password may be read from the storageunit 1000 via the storage/read processing unit 19 and delivered to thetransmitting/receiving unit 11. By transmitting the login requestinformation from the transmission terminal 10 aa to the transmissionmanaging system 50, the transmission managing system 50 on the receivingend can learn the IP address of the transmission terminal 10 ab on thetransmitting end.

Then, the terminal authentication unit 52 of the transmission managingsystem 50 searches the terminal authentication managing table (FIG. 9)in the storage unit 5000 by using the terminal ID and the passwordincluded in the login request information received via thetransmitting/receiving unit 51 as search keys, and determines whetherthe corresponding terminal ID and password are managed in the terminalauthentication managing DB 5002, thus performing terminal authentication(step S23). When the corresponding terminal ID and password are managedin the terminal authentication unit 52, it is determined that the loginrequest is from the transmission terminal 10 having valid access rights.In this case, the status managing unit 53 stores the terminal ID and theoperating status of the transmission terminal 10 aa, the receivedate/time of reception of the login request information, and the IPaddress of the transmission terminal 10 aa in association with oneanother in the terminal managing table (FIG. 10) (step S24). Forexample, the terminal managing table of FIG. 10 stores the operatingstatus “online”, the receive date/time “2009.11.10.13:40”, and theterminal IP address “1.2.1.3” in association with the transmissionterminal ID “01 aa”.

The transmitting/receiving unit 51 of the transmission managing system50 then transmits, via the communication network 2, authenticationresult information indicating the result of authentication by theterminal authentication unit 52 to the request source terminal 10 aathat has made the login request (step S25). In accordance with thepresent embodiment, when it is determined by the terminal authenticationunit 52 that the transmission terminal 10 has the valid access right,the following process is performed.

The terminal extracting unit 54 of the transmission managing system 50searches the destination list managing table (FIG. 11) by using theterminal ID “01 aa” of the request source terminal 10 aa that has madethe login request as a search key, and reads (i.e., extracts) theterminal IDs of candidates for the destination terminal 10B that cancommunicate with the request source terminal 10 aa (step S26). In theillustrated example, the terminal IDs “01 ab”, “01 ba”, and “01 db” ofthe destination terminals 10 ab, 10 ba, and 10 db, respectively,associated with the terminal ID “01 aa” of the request source terminal10 aa are extracted.

Then, the terminal status acquiring unit 55 searches the terminalmanaging table (FIG. 10) by using the terminal IDs “01 ab”, “01 ba”, and“01 db” of the candidates for the destination terminal 10B extracted bythe terminal extracting unit 54 as search keys, and reads the operatingstatus “offline”, “online”, or “online” associated with thecorresponding terminal ID, thus acquiring the operating status of eachof the transmission terminals 10 ab, 10 ba, and 10 db (step S27).

The transmitting/receiving unit 51 then transmits the destination statusinformation including the terminal IDs “01 ab”, “01 ba”, and “01 db” asthe search keys used in step S27, and the operating status “offline”,“online”, or “online” of the corresponding destination terminals 10 ab,10 ba, and 10 db to the request source terminal 10 aa via thecommunication network 2 (step S28). Thus, the request source terminal 10aa can recognize the current operating status of the transmissionterminals 10 ab, 10 ba, and 10 db as candidates for the destinationterminal 10B that can communicate with the request source terminal 10aa.

Further, the terminal extracting unit 54 of the transmission managingsystem 50 searches the destination list managing table (FIG. 11) byusing the terminal ID “01 aa” of the request source terminal 10 aa as asearch key, and extracts the terminal IDs of other request sourceterminals 10A that have registered the terminal ID “01 aa” of therequest source terminal 10 aa as a candidate for the destinationterminal 10B (step S29). For example, in the destination list managingtable of FIG. 11, the terminal IDs of the other request source terminals10A that are extracted are “01 ab”, “01 ba”, and “01 db”.

The terminal status acquiring unit 55 of the transmission managingsystem 50 then searches the terminal managing table (FIG. 10) by usingthe terminal ID “01 aa” of the request source terminal 10 aa that hasmade the login request as a search key, and acquires the operatingstatus of the request source terminal 10 aa (step S30).

Then, the transmitting/receiving unit 51 transmits destination statusinformation to the transmission terminals 10 ba and 10 db whoseoperating status is “online” in the terminal managing table (FIG. 10)among the transmission terminals 10 ab, 10 ba, and 10 db associated withthe terminal IDs “01 ab”, “01 ba”, and “01 db” extracted in step S29.The destination status information includes the terminal ID “01 aa” ofthe request source terminal 10 aa acquired in step S30 and the operatingstatus “online” (steps S31-1 and S31-2). When transmitting thedestination status information to the transmission terminals 10 ba and10 db, the transmitting/receiving unit 51 refers to the IP addresses ofthe terminals managed in the terminal managing table of FIG. 10 based onthe terminal IDs “01 ba” and “01 db”. Thus, the terminal ID “01 aa” ofthe request source terminal 10 aa that has made the login request andthe operating status “online” can be transmitted to each of the otherdestination terminals 10 db and 10 ba that can communicate with therequest source terminal 10 aa as a destination.

In another transmission terminal 10, when a user turns on the powerswitch 109 of FIG. 4 as in step S21, the operating input receiving unit12 of FIG. 5 may initiate processes similar to those of steps S22through S31-1/31-2.

Referring to FIG. 18, a process of narrowing the relay apparatuses 30 isdescribed. In accordance with the present embodiment, the request sourceterminal 10 aa can communicate with at least one of the transmissionterminals 10 ba and 10 db among the candidates of which the operatingstatus is “online” based on the destination status information receivedin step S28. Thus, the following description is made on the assumptionthat the user of the request source terminal 10 aa has selected tocommunicate with the destination terminal 10 db.

When the user presses the operating button 108 of FIG. 3 to select thetransmission terminal 10 db, the operating input receiving unit 12 ofFIG. 5 receives a request for starting communications with thetransmission terminal 10 db (step S41). The transmitting/receiving unit11 of the transmission terminal 10 aa then transmits start requestinginformation including the terminal ID “01 aa” of the request sourceterminal 10 aa and the terminal ID “01 db” of the destination terminal10 db to the transmission managing system 50 (step S42). Thus, thetransmitting/receiving unit 51 of the transmission managing system 50receives the start requesting information and also learns the IP address“1.2.1.3” of the request source terminal 10 aa (transmitting source).

Then, the status managing unit 53 modifies the terminal managing table(FIG. 10) based on the terminal ID “01 aa” of the request sourceterminal 10 aa and the terminal ID “01 db” of the destination terminal10 db that are included in the start requesting information (step S43).Specifically, the status managing unit 53 modifies the fields for theoperating status of the records corresponding to the terminal IDs “01aa” and “01 db” in the terminal managing table (FIG. 10) to “connected”.In this status, the request source terminal 10 aa and the destinationterminal 10 db may not have actually started communicating with eachother but are connected or “busy”. Thus, when another transmissionterminal 10 attempts to communicate with the request source terminal 10aa or the destination terminal 10 db, an audio or visual outputindicating the connected (“busy”) status may be made.

Next, the process of performing a session for selecting the relayapparatus 30 in steps S44 through S48 and steps S61-1 through 66 isdescribed. First, the selection session ID generating unit 56 agenerates a selection session ID used for performing the session forselecting the relay apparatus 30 (step S44). The session managing unit57 then stores and manages the selection session ID “se1” generated instep S44, the terminal ID “01 aa” of the request source terminal 10 aa,and the terminal ID “01 db” of the destination terminal 10 db in thesession managing table (FIG. 12) in the storage unit 5000 (step S45) inassociation with one another.

Then, the narrowing unit 56 of the transmission managing system 50performs, based on the relay apparatus managing DB 5001, the terminalmanaging DB 5003, and the priority managing DB 5006, the primarynarrowing process for narrowing the relay apparatuses 30 for relayingthe communication between the request source terminal 10 aa and thedestination terminal 10 db.

Referring to FIG. 19, the process of step S46 is described in detail.First, the terminal IP address extracting unit 56 b, based on theterminal ID “01 aa” of the request source terminal 10 aa and theterminal ID “01 db” of the destination terminal 10 db that are includedin the communication request information transmitted from the requestsource terminal 10 aa, searches the terminal managing table (FIG. 10),and extracts the IP addresses “1.2.1.3” and “1.3.2.4” of thecorresponding transmission terminals 10 aa and 10 db (step S46-1). Then,the primary selecting unit 56 c selects the relay apparatus IDs 111 a,111 b, and 111 d of the relay apparatuses 30 a, 30 b, and 30 d with theoperating status “online” among the relay apparatuses 30 managed in therelay apparatus managing table (FIG. 8) (step S46-2). Also, the primaryselecting unit 56 c, based on the IP address “1.2.1.3” of the requestsource terminal 10 aa and the IP address “1.3.2.4” of the destinationterminal 10 db extracted in step S46-1, searches the relay apparatusmanaging table (FIG. 8). The search involves determining whether theindividual dot addresses of the IP addresses “1.2.1.2.”, “1.2.2.2”, and“1.3.2.2” of the relay apparatuses 30 a and 30 b, and 30 d selected instep S46-2 correspond to, i.e., whether they are the same as ordifferent from, the individual dot addresses of the IP addresses“1.2.1.3” and “1.3.2.4” of the request source terminal 10 aa and thedestination terminal 10 db (step S46-3).

The priority determining unit 57 c then determines the address prioritypoint for each of the relay apparatuses 30 a, 30 b, and 30 dinvestigated in step 46-3, by referring to the priority managing table(FIG. 13)(step S46-4). FIG. 20 illustrates an example of the result ofcalculating the priority points during the process of narrowing therelay apparatuses 30. Specifically, FIG. 20 illustrates the addresspriority points, the transmission rate priority point, and theintegrated points for each relay apparatus ID. The address prioritypoints include points of the relay apparatus 30 with respect to therequest source terminal 10 aa and points with respect to the destinationterminal 10 db of. The integrated points equal a sum of the higher ofthe two address priority points and the transmission rate prioritypoints.

In accordance with the present embodiment, the IP address “1.2.1.2” ofthe relay apparatus 30 a (ID 111 a; see FIGS. 1 and 8) is “same, same,same, different” with respect to the IP address “1.2.1.3” of the requestsource terminal 10 aa (FIG. 10). Thus, as illustrated in FIG. 20, theaddress priority points of the relay apparatus 30 a with respect to thesource terminal 10 aa equal “5” according to the table of FIG. 13. TheIP address “1.2.1.2” of the relay apparatus 30 a is “same, different,different, different” with respect to the IP address “1.3.2.4” of thedestination terminal 10 db. Thus, the address priority points withrespect to the destination terminal 10 db equal “1”. The IP address“1.2.2.2” of the relay apparatus 30 b (ID 111 b) is “same, same,different, different” with respect to the IP address “1.2.1.3” of therequest source terminal 10 aa. Thus, the address priority points of therelay apparatus 30 b with respect to the source terminal 10 aa equal “3”according to FIG. 13. The IP address “1.2.2.2” of the relay apparatus 30b is “same, different, same, different” with respect to the IP address“1.3.2.4” of the destination terminal 10 db. Thus, the address prioritypoints of the relay apparatus 30 b with respect to the destinationterminal 10 db equal “1”. The IP address “1.3.2.2” of the relayapparatus 30 d (ID 111 d) is “same, different, different, different”with respect to the IP address “1.2.1.3” of the request source terminal10 aa, so that the address priority points of the relay apparatus 30 dwith respect to the source terminal 10 aa equal “1”. Further, the IPaddress “1.3.2.2” of the relay apparatus 30 d is “same, same, same,different” with respect to the IP address “1.3.2.4” of the destinationterminal 10 db, so that the address priority points with respect to thedestination terminal 10 db equal “5”.

Referring back to FIG. 19, the priority determining unit 57 d, based onthe maximum data transmission rate of each of the relay apparatuses 30managed in the relay apparatus managing table (FIG. 8), searches thepriority managing table (FIG. 14), and determines the transmission ratepriority points for each of the relay apparatuses 30 a, 30 b, and 30 dthat have been narrowed down by the primary narrowing process in stepS46-2 (step S46-5). In accordance with the present embodiment, asillustrated in FIG. 8, the maximum data transmission rate of the relayapparatus 30 a is 100 Mbps. Thus, the transmission rate priority is 3points according to the transmission rate priority of FIG. 14.Similarly, because the maximum data transmission rate of the relayapparatus 30 b is 1000 Mbps, the transmission rate priority is 5 points.The maximum data transmission rate of the relay apparatus 30 d is 10Mbps, so that the transmission rate priority is 1 point.

Then, the primary selecting unit 56 c selects two of the relayapparatuses 30 a, 30 b, and 30 d with the higher integrated points (step46-6). In accordance with the present embodiment, as illustrated in FIG.20, the relay apparatus IDs 111 a, 111 b, and 111 d are allocated theintegrated points “8”, “8”, and “6”, respectively. Thus, the relayapparatus 30 a associated with the relay apparatus ID “111 a” and therelay apparatus 30 b associated with the relay apparatus ID “111 b” areselected.

Referring to FIG. 18, when the narrowing process of step S46 (FIG. 19)is completed, the transmitting/receiving unit 51 of FIG. 5 transmitsrelay apparatus narrowing information to the destination terminal 10 dbvia the communication network 2 in order to convey the number of thenarrowed relay apparatuses 30 (step S47). The relay apparatus narrowinginformation may include the number of the relay apparatuses 30 narroweddown in step S46, i.e., “2”; the terminal ID “01 aa” of the requestsource terminal 10 aa; and the selection session ID “se1”. Thus, thetransmission terminal 10 db can be informed of the number of the relayapparatuses 30 and identify the transmission terminal 10 from which therequest for a video conference has been received when performing thesession corresponding to the selection session ID “se1”. Thus, thetransmission terminal 10 db can learn the IP address “1.1.1.2” of thetransmission managing system 50, i.e., the transmitting source of therelay apparatus narrowing information.

The transmission terminal 10 db then transmits reception completioninformation from the transmitting/receiving unit 11 via thecommunication network 2 to the transmission managing system 50,indicating the completion of reception of the relay apparatus narrowinginformation (step S48). The reception completion information may includethe session ID “se1”. Thus, the transmission managing system 50 canlearn the IP address “1.3.2.4” of the transmission terminal 10 db, i.e.,the transmitting source, as well as the completion of transmission ofthe number of the relay apparatuses implemented in the session with thesession ID “se1” as illustrated in FIG. 18.

Referring to FIG. 21, a process of the destination terminal 10 daselecting the relay apparatus 30 is described. First, the transmissionmanaging system 50, prior to starting a video conference, transmitspre-relay request information to each of the relay apparatuses 30 a and30 b narrowed in step S46 (steps S61-1 and 61-2). The pre-relay requestinformation may include the session ID “se1”, the IP address “01 aa” ofthe request source terminal 10 aa, and the destination terminal 10 db.Thus, the relay apparatuses 30 a and 30 b can identify the selectionsession, the request source terminal 10A, and the destination terminal10B. The relay apparatuses 30 a and 30 b can also learn the IP address“1.1.1.2” of the transmission managing system 50 as the transmittingsource of the pre-relay request information.

Then, each of the relay apparatuses 30 a and 30 b transmits pre-transmitrequest information from the transmitting/receiving unit 31 via thecommunication network 2 to the request source terminal 10 aa recognizedin steps S61-1 and 61-2, requesting the transmission of the pre-transmitinformation to the relay apparatuses 30 a and 30 b prior to the start ofthe video conference, the pre-transmit information including a ping(Packet Internet Groper), as will be described later (steps S62-1 and62-2). The pre-transmit information may include the session ID “se1”.Thus, the request source terminal 10 aa, in the process of selecting therelay apparatus 30 implemented with the session ID “se1”, can beinformed of the need to transmit the pre-transmit information to therelay apparatuses 30 a and 30 b, and also learn their IP addresses“1.2.1.2” and “1.2.2.2” as the transmitting sources of the pre-transmitrequest information.

Thus, instead of directly sending the IP address of the destinationterminal 10 db from the transmission managing system 50 to the requestsource terminal 10 aa, first the relay apparatus 3 a is informed of theIP address of the destination terminal 10 db in step S61-1, and then therelay apparatus 30 a requests the request source terminal 10 aa totransmit the pre-transmit request information to the same relayapparatus 30 a in step 61-2. This is to ensure security by not lettingone transmission terminal 10 know the IP address of the othertransmission terminal 10.

Then, the request source terminal 10 aa transmits pre-transmitinformation from the transmitting/receiving unit 11 via thecommunication network 2 to the relay apparatuses 30 a and 30 b (stepsS63-1 and 63-2). The pre-transmit information is transmitted to thedestination terminal 10 db via the relay apparatuses 30 a and 30 b,instead of and prior to the transmission of video data and audio data inorder to measure the required time between transmission by the requestsource terminal 10 aa and reception by the destination terminal 10 db.The pre-transmit information may include a ping for confirming that therequest source terminal 10 aa, the relay apparatuses 30 a and 30 b, andthe destination terminal 10 db are communicatively connected to oneanother; the transmit date/time of transmission of the pre-transmitinformation from the request source terminal 10 aa; and the session ID“se1”. Thus, the relay apparatuses 30 a and 30 b can recognize thetransmission of the pre-transmit information and the IP address“1.2.1.3” of the request source terminal 10 aa, i.e., the transmittingsource of the pre-transmit information, when the session with theselection session ID “se1” is performed.

Then, each of the relay apparatuses 30 a and 30 b relays thepre-transmit information to the IP address “1.3.2.4” of the destinationterminal 10 db included in the pre-relay request information received insteps S61-1 and 61-2 (steps S64-1 and 64-2). Thus, the destinationterminal 10 db can recognize the arrival of the pre-transmit informationand also learn the IP addresses “1.2.1.2” and “1.2.2.2” of the relayapparatuses 30 a and 30 b, i.e., the transmitting sources (relayingsources) of the pre-transmit information when the session with thesession ID “se1” is performed.

Then, the selection processing unit 16 of the destination terminal 10db, based on the pre-transmit information, narrows down the relayapparatuses to one relay apparatus 30 for relaying video data and audiodata during the video conference (step 65).

Referring to FIGS. 5 and 22, the process of step S65 is described indetail. First, the measuring unit 16 a of the selection processing unit16 of FIG. 5 measures the receive date/time of reception, by thetransmitting/receiving unit 11 of the transmission terminal 10 db, ofthe pre-transmit information relayed by the relay apparatuses 30 a and30 b and (step S65-1). Then, the calculating unit 16 b calculates arequired time between transmission and reception of the pre-transmitinformation based on the difference between the receive date/time andthe transmit date/time included in the pre-transmit information, foreach item of the pre-transmit information whose receive time is measured(step S65-2).

The selecting unit 16 c then determines whether, during the session withthe session ID “se1”, all of a number of items of the pre-transmitinformation corresponding to the number of the relay apparatuses 30expected to relay, i.e., “2”, have been received (step S65-3). When notall of the items of the pre-transmission information have been received(“NO” in S65-3), the selecting unit 16 c determines whether apredetermined time (such as 1 minute) has elapsed since the reception ofthe pre-transmit information by the transmission terminal 10 db (stepS65-4). When the predetermined time has not elapsed (“NO” in S65-4), theroutine returns to step S65-1.

On the other hand, when it is determined that all of the items have beenreceived (“YES” in step 65-3), or that the predetermined time haselapsed (“YES” in step S65-4), the selecting unit 16 c selects one ofthe relay apparatuses 30 that has relayed the pre-transmit informationwith the minimum of the required times calculated by the calculatingunit 16 b (step S65-5). In accordance with the present embodiment, therelay apparatus 30 a may be selected when the required time betweentransmission and reception of the pre-transmit information is shorterwhen relayed by the relay apparatus 30 a than by the relay apparatus 30b.

In accordance with the present embodiment, the relay apparatuses 30 arenarrowed down to the relay apparatus 30 a on the side of the destinationterminal 10 db. However, this is merely an example. Preferably, thedestination terminal 10 db may transmit all items of the required timeinformation indicating the required time between transmission andreception of the pre-transmit information to the request source terminal10 aa or the transmission managing system 50, and then the relayapparatuses may be narrowed down to the one relay apparatus 30 a on theside of the request source terminal 10 aa or the transmission managingsystem 50.

The destination terminal 10 db then transmits selection information fromthe transmitting/receiving unit 11 via the communication network 2 tothe transmission managing system 50, the selection informationindicating the selection of the relay apparatus 30 a (step S66). Theselection information may include the session ID “se1” and the relayapparatus ID “111 a” of the selected relay apparatus 30 a. Thus, thetransmission managing system 50, when performing the session with thesession ID “se1”, can recognize that the relay apparatus 30 a has beenselected and that the IP address of the selection informationtransmitting source, i.e., the transmission terminal 10 db, is“1.3.2.4”.

The session managing unit 57 of the transmission managing system 50 thenstores, in the session managing table of the session managing DB 5005(FIG. 12), the relay apparatus ID “111 a” of the finally selected relayapparatus 30 a in the field for the relay apparatus ID of the recordincluding the selection session ID “se1” (step S67-1). Thetransmitting/receiving unit 51 then transmits the relay apparatus ID“111 a” and the IP address “1.3.2.4” of the destination terminal 10 dbto the request source terminal 10 aa (step S67-21). Thereafter, thetransmitting/receiving unit 51 of the transmission managing system 50transmits relay start requesting information to the relay apparatus 30 avia the communication network 2, requesting the start of relaying (stepS68). The relay start requesting information may include the IPaddresses “1.2.1.3” and “1.3.2.4” of the request source terminal 10 aaand the destination terminal 10 db, respectively. Thus, the relayapparatus 30 a, between the transmission terminals 10 aa and 10 db,establishes a session for communicating the video data including thethree resolutions, i.e., low, intermediate, and high resolutions, andaudio data (step S69). Thus, the transmission terminals 10 aa and 10 dbcan start a video conference.

In the foregoing embodiment, in step S47, the transmission managingsystem 50 transmits the relay apparatus narrowing information to thedestination terminal 10 db and then the relay apparatus selectingprocess (step S65) is performed on the side of the destination terminal10 db via steps S48 through S64-1, 64-2. However, this is merely anexample. Preferably, the transmission managing system 50 may transmitthe relay apparatus narrowing information to the request source terminal10 aa in step S47 with the transmitting source and the receiving sourceexchanged between the request source terminal 10 aa and the destinationterminal 10 db, until steps S64-1 and 64-2 inclusive. In this way, therequest source terminal 10 aa may perform the relay apparatus selectingprocess in a step corresponding to step S65 and transmit the selectioninformation in a step corresponding to step S66.

Referring to FIGS. 5 and 23, a process of transmitting and receiving thevideo data and audio data between the request source terminal 10 aa andthe destination terminal 10 db for a video conference is described.First, the request source terminal 10 aa transmits the video data of theobject imaged by the imaging unit 14 a and the audio data of the audioinputted by the audio input unit 15 a to the relay apparatus 30 a fromthe transmitting/receiving unit 11 via the communication network 2 (stepS81). In accordance with the present embodiment, the data transmittedmay include high-quality video data consisting of the low-resolution,intermediate-resolution, and high-resolution images illustrated in FIG.6 and the audio data. Thus, in the relay apparatus 30 a, thetransmitting/receiving unit 31 receives the video data having the threeresolutions and the audio data.

Still referring to FIG. 23, the data quality confirming unit 33 thensearches the modified quality managing table (FIG. 7) by using the IPaddress “1.3.2.4” of the destination terminal 10 db as a search key, andextracts the image quality of the corresponding video data to berelayed, thus confirming the quality of the video data to be relayed(step S82). In accordance with the present embodiment, the confirmedimage quality of the video data is “high-quality”, which corresponds tothe image quality of the video data received by thetransmitting/receiving unit 31. Thus, the video data and the audio dataare transferred to the destination terminal 10 db without modifyingtheir quality (step S83). After the destination terminal 10 db receivesthe video data and audio data via the transmitting/receiving unit 11, animage based on the received video data is displayed on the display 120by the image display control unit 14 b, and an audio output is providedby the audio output unit 15 b based on the received audio data.

Then, the delay detecting unit 17 of the transmission terminal 10 dbdetects a reception delay time of the video data received by thetransmitting/receiving unit 11 at predetermined time intervals (such as1 second intervals) (step S84). In accordance with the presentembodiment, the delay time may be 200 ms. The transmitting/receivingunit 11 of the destination terminal 10 db transmits delay informationindicating the delay time “200 ms” to the transmission managing system50 via the communication network 2 (step S85). Thus, the transmissionmanaging system 50 can recognize the delay time and also recognize theIP address “1.3.2.4” of the delay information transmitting source, i.e.,the transmission terminal 10 db.

Still referring to FIG. 23, the delay time managing unit 60 of thetransmission managing system 50 then searches the terminal managingtable (FIG. 10) by using the IP address “1.3.2.4” of the destinationterminal 10 db as a search key, and extracts the corresponding terminalID “01 db”. Further, the delay time managing unit 60 stores the delaytime “200 ms” indicated in the delay information in the session managingtable (FIG. 12) of the session managing DB 5005, specifically in thefield for the delay time in the record corresponding to the terminal ID“01 db” (step S86). The quality determining unit 58 then searches thequality managing table (FIG. 15) by using the delay time “200 ms” as asearch key, and extracts the image quality “intermediate image quality”of the corresponding video data, thus determining the image quality tobe “intermediate image quality” (step S87).

Then, the transmitting/receiving unit 51 searches the relay apparatusmanaging DB table (FIG. 8) by using the relay apparatus ID “111 a”associated with the terminal ID “01 db” in the session managing table(FIG. 12) as a search key, and extracts the IP address “1.2.1.2” of thecorresponding relay apparatus 30 a (step S88). Thetransmitting/receiving unit 51 then transmits the quality informationindicating “intermediate image quality” of the video data determined instep S87 to the relay apparatus 30 a via the communication network 2(step S89). The quality information may include the IP address “1.3.2.4”of the destination terminal 10 db that has been used as a search key instep S86. Thus, in the relay apparatus 30 a, the modified qualitymanaging unit 34 stores, in the modified quality managing table (FIG.7), the IP address “1.3.2.4” of the transmission terminal 10 as adestination (i.e., the destination terminal 10 db in the illustratedexample) and the image quality “intermediate image quality” of therelayed video data in association with each other (step S90).

Then, the transmission terminal 10 ba, as in step S81, transmits thehigh-quality video data consisting of the low-, intermediate-, andhigh-quality data (step S91) and audio data to the relay apparatus 30 a.Thus, in the relay apparatus 30 a, as in step S82, the data qualityconfirming unit 33 searches the modified quality managing table (FIG. 7)by using the IP address “1.3.2.4” of the destination terminal 10 db as asearch key, and extracts the image quality “intermediate image quality”of the corresponding video data to be relayed, thus confirming the imagequality of the relayed video data (step S92). In accordance with thepresent embodiment, the confirmed image quality may be “intermediateimage quality”, which is lower than the image quality “high-quality” ofthe video data received by the transmitting/receiving unit 31. Thus, thedata quality modifying unit 35 changes the video data quality from“high-quality” to “intermediate image quality”, thus modifying the imagequality of the video data (step S93).

The transmitting/receiving unit 31 then transmits the video data withthe modified image quality “intermediate image quality” and the audiodata whose audio quality is not modified to the transmission terminal 10db via the communication network 2 (step S94). Thus, when there is areception delay in the destination terminal 10 db upon reception of thevideo data, the relay apparatus 30 a modifies the image quality so thatthe participants of the video conference are not annoyed.

Next, a description is given of a process of sharing an entire screendisplaying the material data stored in the storage unit 4000 of theexternal input apparatus 40 after the relay apparatus 30 is determined,with reference to FIG. 26. Specifically, an example is described inwhich information (material data) being displayed on the external inputapparatus 40 aa connected to the transmission terminal 10 aa isdisplayed on the transmission terminal 10 db as a destination terminal.

As described above, after the relay apparatus 30 is determined, therelay apparatus ID “111 a” and the IP address “1.3.2.4” of thedestination terminal 10 db transmitted by the transmission managingsystem 50 in S67-21 are received by the transmitting/receiving unit 11of the transmission terminal 10 aa, and the received relay apparatus ID“111 a” and IP address “1.3.2.4” are stored by the storage/readprocessing unit 19 in the storage unit 1000 (step S67-22).

Referring to FIG. 26, when the external input apparatus 40 aa and thetransmission terminal 10 aa are connected to each other, the connectiondetecting unit 42 of the external input apparatus 40 aa detects theconnection (step S70). Then, the install determination unit 43, asillustrated in FIG. 29, determines whether the display data transmittingunit 452 is already installed (step S71). When it is determined in stepS71 that the display data transmitting unit 452 is not yet installed,the program acquiring unit 44 acquires the data transmitting unit 452stored in the transmission terminal 10 aa and installs it (step S72).Then, the external input apparatus 40 aa sends a request to thetransmission terminal 10 aa for permission for the display dataacquiring unit 451 to perform a process (step S73). When thetransmission terminal 10 aa grants permission to the external inputapparatus 40 aa for performing the process by the display data acquiringunit 451, the display data acquiring unit 451 acquires the display data(step S74). Then, the display data transmitting unit 452 transmits thedisplay data acquired by the display data acquiring unit 451 to thetransmission terminal 10 aa (step S75). When it is determined in stepS71 that the display data transmitting unit 452 is installed, step S72is omitted.

Upon reception of the display data by the external informationtransmitting/receiving unit 18 of the transmission terminal 10 aa, thestorage/read processing unit 19 acquires the relay apparatus ID “111 a”stored in the storage unit 1000 and the IP address “1.3.2.4” of thedestination, i.e., the transmission terminal 10 db (step S77). Then, thetransmitting/receiving unit 11 transmits the display data and the IPaddress “1.3.2.4” of the destination transmission terminal 10 db, to therelay apparatus 30 indicated by the relay apparatus ID “111 a” acquiredin step S77 (step S78). Upon reception of the display data from thetransmission terminal 10 aa in step S78, the relay apparatus 30, basedon the IP address “1.3.2.4” of the transmission terminal 10 db, modifiesthe quality of the display data (step S79), and transmits the displaydata to the transmission terminal 10 db (step S80). The details of theprocess of step S77 may be similar to those of the process of modifyingthe quality of audio data and video data as described above (steps S81through S94).

Still referring to FIG. 26, upon reception of the display data from therelay apparatus 30 by the transmitting/receiving unit 11 of thetransmission terminal 10 db, the image display control unit 14 b causesthe display data to be displayed. In the example illustrated in FIG. 28,the image displayed by the external input apparatus 40 aa is displayedin the left side of the screen based on the display data, while thevideo data of the image imaged by the imaging unit 14 a of thetransmission terminal 10 aa and transmitted by thetransmitting/receiving unit 11 is displayed in an upper-right portion ofthe screen. In a lower-right portion of the screen, there is displayedthe video data imaged by the imaging unit 14 a of the transmissionterminal 10 db.

Main Effects

Thus, in accordance with the present embodiment, the relay apparatus IDof the relay apparatus 30 that relays the audio data and video data isstored in the storage unit 1000 of the transmission terminal 10 aa. As aresult, the display data of material data stored in the storage unit4000 of the external input apparatus 40 that is not managed by thetransmission managing system 50 can be transmitted to the transmissionterminal 10 db of a counterpart of a conference. Because thetransmission managing system 50 does not need to perform a process ofauthenticating the external input apparatus 40, its managing workloadcan be reduced.

When it is desired to share a screen being displayed on an externalinput apparatus 40 that does not have the display data acquiring unit451 or the display data transmitting unit 452, the external inputapparatus 10 can be provided with the display data acquiring unit 451 orthe display data transmitting unit 452 upon connection with thetransmission terminal 10, thus enabling the sharing of the screen.

In the communication network 2, it may be possible to obtain theenvironment of the LANs 2 a through 2 d, such as the IP address of therelay apparatus 30. However, it may be difficult to obtain theenvironment of the Internet 2 i. Thus, initially, the relay apparatuses30 for relaying video data and audio data are narrowed down to two ormore relay apparatuses based on the information of the availableenvironment. Then, prior to actually transmitting or receiving videodata and audio data between the plural transmission terminals 10, thepre-transmit information is transmitted and received instead of thevideo data and audio data. In this way, the relay apparatuses 30 can benarrowed down to one relay apparatus capable of actually relaying thepre-transmit information within the shortest time.

Namely, two or more of the relay apparatuses 30 that are allocated withupper two or more dot addresses of the IP addresses closer to any of thedot addresses of the IP addresses of the transmission terminals 10 areselected. In this way, two or more candidates for the relay apparatus 30that may be finally used can be selected. Thereafter, the pre-transmitinformation is transmitted and received between the request sourceterminal 10A and the destination terminal 10B via the candidate relayapparatuses 30. Then, the two or more candidate relay apparatuses 30 arenarrowed down to one relay apparatus 30 that has the shortest time fortransmission and reception of the pre-transmit information. Thus, thevideo data or audio data can be transmitted and received with thehighest quality available under the existing environment of thecommunication network 2.

In accordance with the present embodiment, when narrowing the relayapparatuses 30, in addition to preferentially selecting the relayapparatuses 30 having the IP address close to the IP addresses of thetransmission terminals 10 that perform a video conference, the maximumdata transmission rate of the relay apparatus 30 may be taken intoconsideration. Thus, the candidates for the relay apparatus 30 can benarrowed by taking into consideration the actual environment of thecommunication network 2.

Further, in accordance with the present embodiment, the narrowingprocess may be performed with regard to the relay apparatuses 30 whoseoperating status is “online”. Thus, the candidates for the relayapparatus 30 can be narrowed by taking into consideration the actualenvironment of the network 2 more accurately.

Preferably, the process of acquiring the display data may involve amirror driver capable of transmitting the generated display datadirectly to a USB driver without passing through a program. In thiscase, the mirror driver may generate the display data, and the USBdriver may transmit the display data to the transmission terminal 10 viathe external unit I/F 118. In this case, there is no need for a programto acquire the display data, so that the resources for executing theprogram can be reduced.

In the foregoing embodiment, a program acquires the video data generatedby the display driver and then transmits the video data to thetransmission terminal 10. Alternatively, the program may acquire adrawing command generated by a GDI and then transmit the command to thetransmission terminal 10 aa. Because the drawing command has less volumethan video data, the network load can be reduced. Preferably, thedisplay data acquiring unit 451 may acquire only the display datadisplayed on a predetermined one of plural screens of a virtual display,and the acquired data may be transmitted by the display datatransmitting unit 452. In this way, the video data being displayed on ascreen other than a predetermined screen can be prevented from beingshared with the conference counterpart, so that materials of highlyconfidential nature can be prevented from being disclosed. In this way,an increased level of security can be obtained.

The transmission managing system 50, the program providing system 90,and the maintenance system 100 according to the present embodiment maybe provided by a single computer or plural computers assigned to thevarious functions or units of any of the systems. When the programproviding system 90 is provided by a single computer, the programproviding system 90 may transmit a program in a lump or in pluralmodules. When the program providing system 90 is provided by pluralcomputers, the plural modules may be transmitted from the correspondingcomputers.

The transmission terminal program, the relay apparatus program, and/orthe transmission managing program may be stored in a recording medium orthe HD 204. The recording medium, the HD 204, or the program providingsystem 90 including the HD 204 may be provided as a program productwhich may be sold nationally or internationally. Thus, users at variouslocations can be provided with the transmission terminal program, therelay apparatus program, and/or the transmission managing program.

In accordance with the present embodiment, by using the modified qualitymanaging table of FIG. 7 and the quality managing table of FIG. 15, thequality of the video data relayed by the relay apparatus 30 is managedin terms of image resolution. However, this is merely an example;preferably, the quality of the video data may be managed in terms of thedepth of image quality of the video data, the sampling frequency of theaudio data, or the bit length of the audio data. While the receivedate/time is managed by using the tables of FIGS. 8, 10, and 12, this ismerely an example. Preferably, only the receive time may be managed.

In accordance with the present embodiment, the IP address of the relayapparatus is managed by the table of FIG. 8 and the IP address of thetransmission terminal is managed by the table of FIG. 10. Preferably,any information capable of identifying the relay apparatus 30 or thetransmission terminal 10 on the communication network 2 may be used. Forexample, the FQDN (Fully Qualified Domain Name) of the relay apparatusor the transmission terminal may be managed. In this case, the IPaddress corresponding to the FQDN may be acquired by a DNS (Domain NameSystem) server. The “relay apparatus identifying information foridentifying the relay apparatus 30 on the communication network 2” mayalso be referred to as “relay apparatus location information indicatingthe location of the relay apparatus 30 on the communication network 2”,or “relay apparatus address information indicating the address of therelay apparatus 30 on the communication network 2”. Similarly, the“terminal identifying information identifying the transmission terminal10 on the communication network 2” may be referred to as “terminallocation information indicating the location of the transmissionterminal 10 on the communication network 2” or “terminal addressinformation indicating the address of the transmission terminal 10 onthe communication network 2”.

In accordance with the present embodiment, a video conference system hasbeen described as an example of the transmission system 1. However, thisis merely an example. Other examples of the transmission system 1 mayinclude an IP (Internet Protocol) telephone system and an Internettelephone system. Preferably, the transmission system 1 may include acar navigation system. In this case, one transmission terminal 30 maycorrespond to a car navigation apparatus mounted on an automobile whilethe other transmission terminal 30 may correspond to a managing terminalor server in a management center for managing the car navigation system.Alternatively, the other transmission terminal 30 may correspond to acar navigation apparatus mounted on another automobile.

Preferably, in the process of acquiring display data, only a portion ofthe data corresponding to an area (which may be referred to as a“window”), of a screen may be acquired instead of the entire screen, aswill be described below. FIG. 27 illustrates an example of a screenbeing displayed by the external input apparatus 40 aa. In this example,the screen includes an area (a) and an area (b). One of these areas maybe selected by operating a mouse 212 and moving a pointer (c) in thescreen of FIG. 27 and shared with the transmission terminal 10 db. Inthis case, the display data of the selected area (a) may be acquired bythe display data acquiring unit 451.

Preferably, the external input apparatus may be provided in advance withthe display data acquiring unit 451 and the display data transmittingunit 452 stored in the storage unit 1000 of the transmission terminal10. In this case, the process of transmitting and receiving the displaydata acquiring unit 451 and the display data transmitting unit 452 canbe omitted, thereby reducing the load on the transmission terminal 10and the external input apparatus 40. In accordance with the presentembodiment, the external input apparatus 40 causes the display apparatus400 to display data. The display apparatus 400 may be separate from orprovided in the external input apparatus 40.

Preferably, the process of step S71 may involve the installdetermination unit 43 determining whether the display data acquiringunit 451 and the display data transmitting unit 452 are alreadyinstalled. In this case, when it is determined in step S71 that thedisplay data transmitting unit 452 is not installed, the programacquiring unit 44 may acquire the display data acquiring unit 451 andthe data transmitting unit 452 stored in the transmission terminal 10 aaand then have them installed (step S73).

Preferably, the external input apparatus 40 aa may be provided inadvance with the display data acquiring unit 451, thus eliminating theprocess performed by the install determination unit 43. The display dataacquired by the display data acquiring unit 451 may be written into thestorage unit 1000 of the mounted transmission terminal 10 aa so that thedisplay data transmitting unit 452 can be omitted.

Although this invention has been described in detail with reference tocertain embodiments, variations and modifications exist within the scopeand spirit of the invention as described and defined in the followingclaims.

1. A transmission terminal for transmitting video data and display dataof a screen shared with another transmission terminal to the othertransmission terminal via a predetermined relay apparatus, thetransmission terminal comprising: a storage unit configured to storerelay apparatus information of the relay apparatus to which thetransmission terminal transmits the video data; a receive unitconfigured to receive the display data from an external input apparatusconnected to the transmission terminal; and a transmitting unitconfigured to transmit the display data received by the receive unit tothe relay apparatus indicated by the relay apparatus information storedin the storage unit.